Heat dissipation device

ABSTRACT

A heat dissipation device includes a fan and a heat sink located at the air outlet of the fan. The heat sink includes a first fin set arranged at a central portion of the air outlet, and two second fin sets respectively arranged at a side portion of the air outlet. The first fin set includes a plurality of first fins with a first passage defined between each two neighboring first fins. Each of the second fin sets includes a plurality of second fins with a second passage defined between each two neighboring second fins. Each of the second fin sets defines an undercut near the air outlet of the fan. The first passages communicate with the central portion of the air outlet of the fan. Each of the undercuts of the second fin sets communicates with corresponding side portion and corresponding second passage.

BACKGROUND

1. Technical Field

The disclosure relates to heat dissipation devices, and particularly to a heat dissipation device incorporating a fin assembly.

2. Description of Related Art

A heat dissipation module is often applied to dissipate heat from heat generating components, such as central procession units (CPUs). Generally, a conventional heat dissipation module includes a centrifugal fan and a fin assembly arranged at an air outlet of the fan.

During operation, the fan generates airflow through the fin assembly to take away the heat of the fin assembly absorbed from the heat generating component. However, an amount of the airflow at two sides of the air outlet is larger than an amount of the airflow at a central portion of the air outlet, therefore, dust will deposit on two laterally sides of the fin assembly corresponding to the two sides of the fan along with the airflow.

Thus, it is desired to overcome the described limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembled view of a heat dissipation device, according to an exemplary embodiment of the present disclosure.

FIG. 2 is an exploded, isometric view of the heat dissipation device of FIG. 1.

FIG. 3 is an assembled, inverted view of a heat sink of the heat dissipation device of FIG. 2.

FIG. 4 is a top plan view of a fan and a heat sink of the heat dissipation device of FIG. 1.

DETAILED DESCRIPTION

FIGS. 1 and 2 show a heat dissipation device 100 in accordance with an exemplary embodiment. The heat dissipation device 100 includes a first heat absorbing substrate 10, a second heat absorbing substrate 20, a heat sink 30, two first heat pipes 60 thermally interconnecting the first heat absorbing substrate 10 and the heat sink 30, a second heat pipe 70 thermally interconnecting the second heat absorbing substrate 20 and the heat sink 30, and a fan 80 arranged a lateral side of the heat sink 30.

In the present embodiment, the fan 80 is a centrifugal fan, which includes a holder 81, a cover 83 engaged with the holder 81 to form a cavity, and an impeller 82 received in the cavity. The holder 81 includes a bottom plate 84 and a sidewall 85 perpendicularly and upwardly extending from a periphery of the bottom plate 84. The cover 83 defines an air inlet 86 therein. The holder 81 defines an air outlet 87 between two ends of the sidewall 85. A curved tongue portion 88 protrudes inwardly from the sidewall 85, and is adjacent to the air outlet 87.

In the present embodiment, the first and second heat absorbing substrates 10, 20 are made of metal which has a high thermal conductivity, such as copper, aluminum, or stainless steel. The first and second heat absorbing substrates 10, 20 are respectively configured for contacting electronic elements and absorbing heat generated therefrom.

Also referring to FIG. 3, the heat sink 30 is located at the air outlet 87 of the fan 80, and the heat sink 30 has a first surface 32 towards the fan 80 and a second surface 33 away from the air outlet 87 of the fan 80. The heat sink 30 defines a U-shaped through groove 31 at the first surface 32 to receive condensation portions of the first heat pipes 60 and the second heat pipe 70. The heat sink 30 includes a first fin set 40 and two second fin sets 50 arranged at two opposite sides of the first fin set 40.

The first fin set 40 includes a plurality of first fins 42 stacked together. Each first fin 42 is parallel to and spaced from a neighboring first fin 42. Each first fin 42 includes a first main body 420 and a pair of first flanges 422 bent horizontally from a top and a bottom of the first main body 420. A first passage 43 is defined between the first main bodies 420 of each two neighboring first fins 42 for airflow generated by the fan 80. An upper portion of the first main body 420 of each first fin 42 defines a cutout exposed to the air outlet 87 of the fan. The cutouts of the first fins 42 cooperatively define the through groove 31.

Each of the second fin sets 50 includes a plurality of second fins 52. The second fins 52 of each of the second fin sets 50 are stacked together. The two second fin sets 50 sandwich the first fin set 40 therebetween. Each second fin 52 includes a second main body 520 and an extending portion 523 extending from the second main body 520 to the fan 80. A pair of second flanges 522 are bent horizontally from a top and a bottom of each of the second main body 520 and the extending portion 523. A second passage 53 is defined between each two neighboring second fins 52 for airflow generated by the fan 80 with a width the same as that of the second flange 522. The second fins 52 are similar to the first fins 42. The difference of each second fin 52 from each first fin 42 is that a lower portion of each second fin 52 is cut to define an undercut 54, and the undercut 54 is near the fan 80 and communicates with the through groove 31 of the heat sink 30. In other words, each of the second fins 52 has an L-shaped side profile and each of the undercuts 54 is defined below the extending portions 523 and between the second main bodies 520 and the air outlet 87 of the fan 80. Front ends of the extending portions 523 of the second fins 52 are parallel to the first surface 32 of the heat sink 30. Front sides of the second main bodies 520 of the second fins 52 near the undercuts 54 is defined downwards and slantwise away from the fan 80.

In the present embodiment, a top portion of the heat sink 30 near the air outlet 87 of the fan 80 defines a notch for receiving an end portion of the cover 83 of the fan 80.

Also referring to FIG. 4, in the heat dissipation device 100, the first fin set 40 is arranged at a central portion 90 of the air outlet 87, and the second fin sets 50 are arranged at two laterally side portions 89 of the air outlet 87 of the fan 80. Each of the undercuts 54 communicates with corresponding second portion 89 and corresponding second passage 53. During operation of the heat dissipation device 100, the impeller 82 of the fan 80 rotates and drives airflow from the air inlets 86 into the cavity, and then to the air outlet 87. Air pressure in the two laterally side portions 89 of the air outlet 87 is larger than air pressure in the central portion 90 of the air outlet 87, and the undercuts 54 of the second fin sets 50 correspond to the laterally side portions 89 of the air outlet 87; therefore, most dust enter the two laterally side portions 89 of the air outlet 87, and vent from the undercuts 54 of the second fin sets 50 along with the airflow. Therefore, it can prevent dust from entering the heat sink 30 via the second passages 53.

It is to be further understood that even though numerous characteristics and advantages have been set forth in the foregoing description of embodiments, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat dissipation device comprising: a fan defining an air outlet at one side thereof, the air outlet comprising a first portion and two second portions, air pressure in each of the second portions being larger than air pressure of the first portion; and a heat sink being located at the air outlet of the fan, the heat sink comprising a first fin set arranged at the first portion, two second fin sets respectively arranged at the second portions, the first fin set comprising a plurality of first fins stacked together with a first passage being defined between each two neighboring first fins, each of the second fin sets comprising a plurality of second fins stacked together with a second passage being defined between each two neighboring second fins, each of the second fin sets defining an undercut near the air outlet of the fan, the first passages communicating with the first portion of the air outlet of the fan, each of the undercuts of the second fin sets communicating with corresponding second portion and corresponding second passage.
 2. The heat dissipation device of claim 1, further comprising a heat pipe, wherein the heat sink defines a through groove to receive the heat pipe, the through groove being U-shaped and communicating with the air outlet of the fan.
 3. The heat dissipation device of claim 1, wherein each first fin comprises a first main body and a pair of first flanges bent horizontally from a top and a bottom of the first main body, each first flange being abutted with a first flange of a neighboring fin, the first passage being formed between every two adjacent fins.
 4. The heat dissipation device of claim 3, wherein each of the second fins comprises a second main body and an extending portion extending from the second main body, each of the undercuts being defined below the extending portions and between the second main bodies and the air outlet of the fan.
 5. The heat dissipation device of claim 4, wherein each of the second fins is L-shaped and has a pair of second flanges bent horizontally from a top and a bottom of the second main body and the extending portion.
 6. The heat dissipation device of claim 1, wherein the fan is a centrifugal fan, the first portion being a central portion of the air outlet, the second portions being located at two opposite sides of the air outlet.
 7. A heat dissipation device comprising: a centrifugal fan defining an air outlet at one side thereof; and a heat sink being located at the air outlet of the fan, the heat sink comprising a first fin set arranged at a central portion of the air outlet, two second fin sets respectively arranged at two opposite side portions of the air outlet, the first fin set comprising a plurality of first fins stacked together with a first passage being defined between each two neighboring first fins, each of the second fin sets comprising a plurality of second fins stacked together with a second passage being defined between each two neighboring second fins, each of the second fin sets defining an undercut near the air outlet of the fan, the first passages communicating with the central portion of the air outlet of the fan, each of the undercuts of the second fin sets communicating with corresponding side portion of the air outlet of the fan and the corresponding second passage.
 8. The heat dissipation device of claim 7, further comprising a heat pipe, wherein the heat sink defines a through groove to receive the heat pipe, the through groove being U-shaped and communicating with the air outlet of the fan.
 9. The heat dissipation device of claim 7, wherein each first fin comprises a first main body and a pair of first flanges bent horizontally from a top and a bottom of the first main body, each first flange being abutted with a first flange of a neighboring fin, the first passage being formed between every two adjacent fins.
 10. The heat dissipation device of claim 9, wherein each of the second fins comprises a second main body and an extending portion extending from the second main body, each of the undercuts being defined below the extending portions and between the second main bodies and the air outlet of the fan.
 11. The heat dissipation device of claim 10, wherein each of the second fins is L-shaped and has a pair of second flanges bent horizontally from a top and a bottom of the second main body and the extending portion. 